Insulating plug

ABSTRACT

A demountable insulating plug formed of a &#39;&#39;&#39;&#39;biscuit&#39;&#39;&#39;&#39; of selected insulating material and desired shape, is secured at one flat surface thereof to a cap of substantially larger peripheral dimensions, and formed of a preferably metallic material having good heat dissipating properties, such as aluminum. A handle, formed of a strip of resilient metal and pointed at either end, is extendably disposed with an arcuate configuration through diametrically opposed slots in the cap. Lock tabs are formed in the cap. Lock tabs are also formed in the extended portion of the handle which engage the lock tabs of the cap to prevent withdrawing the handle from the cap. To install, the handle is pulled away from the cap to retract the end portions, and the plug is placed in position in the hole in the insulation of a preinsulated pipe which is to be plugged. Natural resiliency of the material and pressure applied against the handle tend to straighten the latter, which drives the pointed ends thereof radially outwardly into the surrounding insulating material. The resiliency of the handle tends to maintain the pointed ends into the insulation, whereby the plug is securely held in position.

United States Patent Higuera 51 Apr.25, 1972 I INSULATING PLUG Robert E.lliguera, Lafayette, Calif.

[73] Assignee: San Roy Development Co., Inc., San

Rafael, Calif.

[22] Filed: July 17,1970

[2i] Appi.No.: 55,718

[72] Inventor:

[52] US. Cl ..l38/90, 220/24 H, 220/55 K 1,837,346 12/1931 Thomas et ai...i38/89 Primary Examiner-Houston S. Bell, Jr. Attorney-Fryer,Tjensvold, Feix, Phillips & Lempio ABSTRACT A demountable insulatingplug formed of a biscuit" of selected insulating material and desiredshape, is secured at one flat surface thereof to' a cap of substantiallylarger peripheral dimensions, and formed of a preferably metallicmaterial having good heat dissipating properties, such as aluminum. Ahandle, formed of a strip of resilient metal and pointed at either end,is extendably disposed with an arcuate configuration throughdiametrically opposed slots in the cap. Lock tabs are formed in the cap.Lock tabs are also formed in the extended portion of the handle whichengage the lock tabs of the cap to prevent withdrawing the handle fromthe cap. To install, the handle is pulled away from the cap to retractthe end portions, and the plug is placed in position in the hole in theinsulation of a preinsulated pipe which is to be plugged. Naturalresiliency of the material and pressure applied against the handle tendto straighten the latter, which drives the pointed ends thereof radiallyoutwardly into the surrounding insulating material. The resiliency ofthe handle tends to maintain the pointed ends into the insulation,whereby the plug is securely held in position.

9 Claims, 3 Drawing Figures PATENTEU APR 2 5 I972 INVENTOR.

ROBERT E. HIGUERA ATTORNEYS INSULATING PLUG BACKGROUND OF THE INVENTIONThe invention relates to a readily removable, and thus reusable,insulating plug for replugging holes cut into insulation disposed aroundthe various pipes, tanks, etc., of cryogenic or high temperature systemssuch as are employed, for example, in refineries, chemical manufacturingor processing plants, and the like.

BACKGROUND OF THE INVENTION AND PRIOR ART ln cryogenic, hightemperature, etc., systems such as employed in refineries and chemicalprocessing plants, various pipe, tank, and other members are required toefficiently transport very cold (cryogenic temperatures) or very hot(for instance, 1,400 F.) fluids, which may also be caustic or corrosivein nature. Accordingly the pipes, tanks, and other members, are coveredwith various types and configurations of insulating material; e.g.,preformed lengths of insulation defining half cylinders which areclamped together about the pipes; premolded insulation formed directlyon the pipes; strips of insulation wrapped around the pipes; etc. Toprevent pipe failure in such systems, it is desirable and necessary toperiodically check the erosive effects of the fluids in the pipe.

One of the preferred procedures is to employ an ultrasonic test devicewhich provides means for nondestructively detecting the thickness of thepipe wall in place, to thus provide an indication of the condition ofthe pipe. However, as generally known in the art, such ultrasonic testdevices employ ultrasonic transducers which must be held or otherwisesecured immediately against the metal of the pipe wall. Thus a plug ofthe insulating material must be removed from the insulation disposedabout the pipe, at specified points therealong where tests are to bemade. After the tests are made and the transducer is removed fromagainst the pipe, it is desirable to replug the hole in the insulationto block heat loss or gain to protect personnel from being burned byaccidental contact against the exposed pipe, etc. Obviously the plug ofinsulation originally removed from the insulated pipe cannot bereinserted into the hole since it would not stay in place. Further theplug of insulation is not readily adaptable with some mechanism whichwould hold it in place.

Various other demountable insulating plug configurations have beentried, however, none are presently available which provide all thefollowing required parameters: The plug should be operable using onlyone hand; it must insulate as well or nearly as well as the permanentsurrounding insulation; it must be sufficiently insulated to preventpersonnel burns if deliberately touched or brushed against by accident;it must be reasonably economical to market and/or fabricate; it shouldnot fall out of position if it is jarred or brushed against, or if it issubject to vibration; and it should be reusable for economic reasons.

SUMMARY OF THE INVENTION The present invention provides a preferredinsulating plug configuration which meets all the aforementionedrequirements. A plug or biscuit" of insulating material having a sizeand shape slightly smaller than the size and shape of the hole formed inthe pipe insulation, is secured as by means of a bolt, screw, adhesives,etc., to a slightly larger dimensioned cap of a heat dissipatingmaterial, such as aluminum. A handle, formed of a flat, resilient, stripof poor heat conducting material such as, for example, stainless steel,is disposed through a pair of slots in the cap. The end portions of thehandle protrude through the slots and extend generally radially outwardfrom the biscuit" circumference. The ends of the handle are pointed andextend into the surrounding pipe insulation to firmly secure the plugthereto. The resiliency of the handle holds the pointed ends, in theextend position and locked into the surrounding insulation.

In use, the arcuate handle is pinched and simultaneously pulled awayfrom the cap with the fingers of one hand, which action tends to furtherarch the handle, causing the pointed ends thereof to lie substantiallyagainst the circumference of the biscuit. With the pointed ends in sucha retracted position, the plug may be inserted into'or withdrawn from,the hole in the pipe insulation. When installing, a slight pressureagainst the arch of the handle and the natural resiliency thereof tendsto straighten the handle, whereby the pointed ends are driven into thepipe insulation surrounding the plug. Detents or lock tabs integrallyformed as part of the slots during the process of fabricating the capoppose matching lock tabs formed in the pointed ends of the handle,whereby locking action between respective lock tabs preventsaccidentally withdrawing the handle from the cap.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan of an embodiment ofthe invention, assembled and installed in position within a hole in theinsulation of an insulated wall member.

FIG. 2 is a cross section taken along section line 2-2 of FIG. 1,showing the fastening action of the handle when the invention is inposition, wherein one end of the handle is cross sectioned to show thelock tab therein.

FIG. 3 is a cross section similar to that of FIG. 2, showing theinvention when the handle is retracted, as when installing or removingthe plug into or from a hole in the wall member insulation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, thereis shown a portion of a wall member 10 such as a pipe or tank, or othersimilar member for carrying or containing very high or very lowtemperature fluids, etc., which member 10 is accordingly provided withan insulating material 12 having properties commensurate with theparticular use of the member 10. Thus the insulating material 12 may beany of the various refractory materials such as magnesium carbonate,fire brick, etc., or any of the various glass fiber insulations, spunglass, etc., either wrapped around the member 10 or suitably held by acovering material such as a thin metal layer orcanvas material.

The pipes, tanks, etc., depicted by wall member 10 are adapted to handleextremely low temperatures in the cryogenic range, or very hottemperatures of the order of, for example, 1,400 F. The member 10 mayaccordingly be formed of various metals, alloys thereof, ceramics, etc.,capable of withstanding the extreme temperatures. A hole 14 is formed byremoving a plug (not shown) of the insulating material 12, and may be ofany desired shape, e.g., circular, rectangular, hexagonal, etc., therebyexposing a corresponding portion of the member 10. A removable,insulating plug 16 in accordance with the invention, is shown installedwithin the hole 14.

The removable insulating plug 16 of the invention contemplates thecombination of; insulating plug means of selected insulating material(hereinafier referred to as a biscuit" 18 to distinguish it from themember 10 insulation); heat dissipating cap means 20 selectibly securedto the insulating biscuit l8, and resilient handle means 22 associatedwith the cap means 20 and the biscuit l8, and adapted to retractablyengage the sidewalls of the hole 14 in the insulation 12, to firmlysecure the invention thereinto. Although a specific embodiment of theplug 16 is described herein by way of example only, it is to beunderstood that various modifications may be made thereto while stillretaining the above basic invention combination, as further detailedbelow.

Thus the insulating biscuit 18 is formed of a suitable insulatingmaterial, capable of withstanding and shielding against the extremetemperatures found in the cryogenic systems, and/or high temperaturesystems of previous mention. Various refractory materials such as firebrick, as well as glass fiber insulating materials are available,wherein the more solid insulating materials can be formed in the shapeof the biscuit 18, whereas a less consolidated material such as glassfiber etc. may be held within an enclosure of suitable shape.

The biscuit 18 has a shape and dimensions commensurate with the shapeand dimensions of the hole 14. That is, the outside dimensions of thebiscuit 18 are slightly smaller than the inside dimensions of the hole14. Accordingly a narrow annular space 24 is provided between thebiscuit 18 and the confronting surface of the hole 14. Likewise thebiscuit thickness is selected to provide an air space 26 between it andthe confronting surface of the member 10, while still retainingsufficient thickness of the biscuit to provide the required degree ofinsulation.

The outer circumferential edge of the biscuit 18 adjacent the cap 20, isbeveled at a selected angle, as indicated by numeral 28, to allow thehandle to clear the edge of the biscuit l8 and engage the cap 20, and toallow extending the outer circumference of the biscuit 18 towards thesurrounding sidewalls of the hole 14, to thereby decrease the width ofthe annular space 24 as much as possible without interferring with thetranslatable action of the handle means 22, as further described infra.

A cap means (hereinafter referred to as cap 20), preferably a thin, flatdisc of a material having good heat dissipating properties such as, forexample, aluminum, etc., is connected to biscuit 18 and has an outsidediameter or overall dimensions,

substantially greater than the diameter, or overall dimensions, of thehole 14. Cap 20 is provided with a pair of diametrically opposed slots30, formed as by a stamping operation, wherein the displaced material ofeach slot is depressed toward the beveled edge 28 of the biscuitcircumference, to lie substantially parallel thereto at a selecteddistance therefrom to pro vide detents or lock tabs 32 integral with theslots 30.

A bolt 34 extends through the cap 20 and the biscuit l8, and theseelements are secured together by a washer and nut 36 threaded to thebolt 34. Note that the biscuit 18 is provided with a recess 38 wherebythe washer and nut 36 are countersunk to provide an air space betweenthem and the confronting surface of the member 10. The bolt 34/nut 36combination may be of metal or, in very high heat situations, may beformed of various ceramics or porcelains, or other high temperatureresistant materials which can be shaped or molded to provide a fastenermeans.

Although the biscuit 18 is herein shown secured to the cap 20 via. thebolt 34/nut 36 fastening means, it is to be understood that the twoelements 18, 20 may be secured together as by means of any adhesive (notshown) capable of withstanding the extremely low or high temperatures.In a further embodiment tabs may be stamped from the cap 20 and bentdownwardly into matching grooves or holes (not shown) in the biscuit 18,to secure the latter to the cap 20. When employing an unconsolidatedinsulating material such as glass fiber, a pre-formed enclosure meansmay be disposed about the insulating material with the enclosure meansbeing secured to the cap 20.

The air space 26 provides some insulation between the wall member andthe confronting parts of the plug 16, e.g., the biscuit l8, and the bolt34/nut 36, whereby a substantial amount of the heat radiated by themember 10 is blocked prior to reaching the plug 16. Note further thatthe cap 20 acts as a heat sink since it has good heat conducting ordissipating properties. Thus the cap 20 not only radiates the heat whichis introduced by conduction from the member 10, but also the heatdelivered by contact with the bolt 34.

As previously mentioned, various insulated wall member assemblies areprovided with insulation 12 which, in turn, may have a thin cover of ametallic material such as aluminum, in order to protect the insulation12. Since the heat dissipating cap 20 is in contact with this metalcover (not shown) along its outermost periphery, the cap 20 furthertends to act as a heat conductor which conducts and thus dissipates theheat it receives from the member 10 into the metal cover of theinsulating material 12.

The resilient handle means (hereinafter referred to as handle 22) isformed from a thin strip of a resilient material, preferably with poorheat conducting properties. The handle 22 is provided with end portions41 of smaller width than that of a central'portion 43, which endportions define pointed ends, as indicated at 40. Forming the narrowerend portions 41 provides shoulders 42 between portions 41 and thecentral portion 43, which engage the cap 20 when the handle 22 isinserted through the slots 30, as when assembling the plug 16. Detentsor lock tabs 44 are stamped in the end portions 41 of the handle 22, andprotrude inwardly towards the center of the cap 20 and biscuit 18. Thusupon assembly, the lock tabs 44 of the handle means combine with thelock tabs 32 of the cap 20 to provide handle locking means that preventswithdrawing the handle 22 from its position within the slots 30 FIG. 3shows the plug 16 of the invention with the handle 22 retracted, as whenthe plug is removed from or replaced into the hole 14 in the insulatingmaterial 12. The fingers of one hand may be used to grasp the handle 22at the center portion 43, while applying the remaining fingers againstthe cap 20, whereby the central portion of handle 22 is pulled away fromthe cap 20. This action causes the handle 22 to assume a more acutelyarcuate, e.g., circular, condition whereby the end portions 41 of thehandle 22 assume orientations which approach a parallel to the outercircumferential surface of the biscuit 18. The pointed ends 40 (and theend portions 41) are thereby withdrawn from the surrounding insulatingmaterial 12 and into the annular space 24. Thus the plug 16 may berepeatedly inserted into, or withdrawn from, the hole 14.

In use, in the situation where the plug 16 is to be inserted into thehole 14, the plug 16 is grasped by the fingers of one hand as previouslydescribed, whereby the handle 22 is pulled until the lock tabs 44thereof engage the lock tabs 32 of the cap 20. The plug 16 may be theninserted into the which approach a parallel to the outer circumferentialsurface of the biscuit 18. The pointed ends 40 (and the end portions 41)are thereby withdrawn from the surrounding in sulfating material 12 andinto the annular space 24. Thus the plug 16 may be repeatedly insertedinto, the hole 14, and the periphery of the cap 20 is urged against thesurface of the insulation 12, as is shown in FIG. 3. The handle 22 isthen released, whereupon pressure against the handle 22 with the fingersor the palm of the hand, in conjunction with the tendency for the handle22 to assume a straight position due to its resiliency, causes thehandle to straighten whereby the pointed ends 40 are driven into theinsulating material 12 as shown in FIG. 2. This secures the plug 16firmly to the insulation 12. The resiliency of the handle means 22prevents the plug 16 from being disclocated by vibrations, etc., untilremoval is desired. Note the penetration of the end portions 41 islimited by theshoulders 42 which engage theupper surface of the cap 20in the region of the slots 30.

The combination of the air space 26, the insulating biscuit l 8,-and theheat dissipating cap means 20, thus provides for the dissipation of theheat which normally would radiate from the exposed surface of the wallmember 10. The temperature of the cap 20 remains sufficiently low toallow personnel to touch it without undue discomfort. Likewise, thetemperature of the handle 22 remains low enough to be grasped with thebare hand, even though the (exposed) surface of the wall member 10 mayhave a temperature of the order of 1 ,400 F.

Note that the locking means, viz, the lock tabs 32,32 and 44,44, may berearranged other than shown, or may assume configurations other thanthat of the engaging tabs. For example, the lock tabs 32 of the cap maybe bent sharply downward and out from the outer edge of the slots 30,and the lock tabs of the handle may be bent outwardly and up to engagerespective tabs 32. On the other hand, either pair of lock tabs 32 or 44may be replaced by other means which would engage the remaining locktabs. For example, blocks of material may be secured to the handle 22 inplace of tabs 44, which blocks would bear against the confronting edgesof the tabs 32 when the end portions 41 are retracted, to preventwithdrawing the handle 22 from the slots 30. Thus various configurationsare possible for the handle locking means.

In addition the handle 22 may include more than a pair of end portions41, e.g., it may have 3, 4, etc., end portions extending from a centralportion, wherein all the respective pointed ends would extend into thesurrounding insulating material to secure the plug 16. A hole in thecentral portion would allow insertion of a finger whereby the handlecould be retracted.

On the other hand, the resilient handle 22 may employ a single endportion 41, translatably disposed through a single slot 30, andresiliently welded or hinged at its other end to the cap 20. lnthisembodiment (not shown) a radially protruding portion of the cap extendsdownwardly therefrom diametrically opposite the end portion 41, toengage the surrounding insulating material 12 at that side of the plug16.

Although the plug 16, described herein by way of example only, utilizesa single handle 22 and replugs a relatively small hole 14, thecombination may be utilized to plug a relatively large hole of, forexample, several inches long and a few inches wide, by employing acorrespondingly larger biscuit of insulating material and associatedcap. A pair of handles are disposed in the cap, in spaced apart parallelrelation within two pairs of respective slots in the cap. The pointedends of each handle extend outwardly from under the (longer) lateraledges of the corresponding cap means. A plug of such larger dimensionsmay require a hinge disposed transverse to its longer length at themidpoint thereof, whereby the insulating plug may hinge slightly toprovide a better fit against a curved wall member.

What is claimed is:

l. A removable insulation plug for replugging a hole formed in aninsulating material layer disposed about a preinsulated member,comprising the combination of;

insulator plug means formed of a selected insulating material and havingdimensions commensurate with the dimensions of the hole formed in theinsulating material of the preinsulated member;

fastener means including resilient handle means translatably secured tothe insulator plug means;

said resilient handle means including at least one locking portionthereof extending radially outwardly beyond the periphery of said plug.

2. The insulating plug of claim 1 further including a cap of heatdissipating material integral with the insulator plug means, said caphaving an outer periphery which extends beyond the periphery of theinsulator plug means, said cap further having an opening therein forreceiving therethrough the extendable portion of the resilient handlemeans.

3. The insulating plug of claim 2 wherein the cap is secured to one flatsurface of the insulator plug means and includes a plurality of spacedslots, and said resilient handle means includes a plurality ofextendable portions translatably disposed through said respective slots.

4. The insulating plug of claim 3 wherein the resilient handle meansfurther includes a strip of resilient material having end portionsthereof translatably disposed through said plurality of slots to definesaid extendable portions, the end portions of said extendable portionsprotruding outwardly and downwardly beyond the periphery of said plug.

5. The insulating plug of claim 4 further including locking meansintegral with the resilient handle means and also the cap, andengageable when the end portions of the handle means are retracted fromthe surrounding insulating material layer to prevent withdrawing thehandle means from the cap.

6. The insulating plug of claim 5 wherein the thickness of the insulatorplug means is substantially less than the thickness of the surroundinginsulating material layer to provide an air space between theconfronting surfaces of the insulator plug means and the preinsulatedmember.

7. The insulating plug of claim 5 wherein the relative dimensions of theinsulator plug means and the hole formed in the insulating materialprovide an annular space therebetween of sufficient width to receive theend portions of the handle means therein upon their retraction from thesurrounding insulatilng material layer.

8. e insulator plug of claim 1 wherein at least one portion of saidhandle extends outwardly and downwardly beyond the periphery of saidinsulator plug and into the insulation surrounding said hole when saidplug is in place on said preinsulated member.

9. A fastener means for removably securing an insulator plug within ahole defined by a surrounding layer of insulating material disposed upona preinsulated member comprising a resilient handle translatably securedto said insulator plug, and at least one extended portion afiixed tosaid resilient handle and extending radially outwardly and downwardlybeyond the periphery of said plug and into engagement within saidinsulating material layer when said plug is positioned in said hole.-

* ii I! t UNITED STATES PATENT OFFICE v CERTIFICATE OF CORRECTION PatentNo. 3,658,096 Dated April 25, 1972 Inventor(s) ROBERT E. HIGUERA It: iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In DESCRIPTION OF THE PREFERRED EMBODIMENTS, Column L,

Line 32 after "inserted into the Line 37 incl.

delete: "which approach a parallel to the outer circumferential surfaceof the biscuit 18. The pointed ends TD (and the end portions 41) arethereby withdrawn from the surrounding in sulfating material 12 and intothe annular space 2 Thus the plus 16 may be repeatedly inserted into,the' Signed and sealed this 26th day of September 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer 1 Commissionerof Patents FORM PO-IOSO (IO-69) USCOMM-DC 60376-969 0.5. eon-nun numucorncz: Inn o-su-:u

1. A removable insulation plug for replugging a hole formed in aninsuLating material layer disposed about a preinsulated member,comprising the combination of; insulator plug means formed of a selectedinsulating material and having dimensions commensurate with thedimensions of the hole formed in the insulating material of thepreinsulated member; fastener means including resilient handle meanstranslatably secured to the insulator plug means; said resilient handlemeans including at least one locking portion thereof extending radiallyoutwardly beyond the periphery of said plug.
 2. The insulating plug ofclaim 1 further including a cap of heat dissipating material integralwith the insulator plug means, said cap having an outer periphery whichextends beyond the periphery of the insulator plug means, said capfurther having an opening therein for receiving therethrough theextendable portion of the resilient handle means.
 3. The insulating plugof claim 2 wherein the cap is secured to one flat surface of theinsulator plug means and includes a plurality of spaced slots, and saidresilient handle means includes a plurality of extendable portionstranslatably disposed through said respective slots.
 4. The insulatingplug of claim 3 wherein the resilient handle means further includes astrip of resilient material having end portions thereof translatablydisposed through said plurality of slots to define said extendableportions, the end portions of said extendable portions protrudingoutwardly and downwardly beyond the periphery of said plug.
 5. Theinsulating plug of claim 4 further including locking means integral withthe resilient handle means and also the cap, and engageable when the endportions of the handle means are retracted from the surroundinginsulating material layer to prevent withdrawing the handle means fromthe cap.
 6. The insulating plug of claim 5 wherein the thickness of theinsulator plug means is substantially less than the thickness of thesurrounding insulating material layer to provide an air space betweenthe confronting surfaces of the insulator plug means and thepreinsulated member.
 7. The insulating plug of claim 5 wherein therelative dimensions of the insulator plug means and the hole formed inthe insulating material provide an annular space therebetween ofsufficient width to receive the end portions of the handle means thereinupon their retraction from the surrounding insulating material layer. 8.The insulator plug of claim 1 wherein at least one portion of saidhandle extends outwardly and downwardly beyond the periphery of saidinsulator plug and into the insulation surrounding said hole when saidplug is in place on said preinsulated member.
 9. A fastener means forremovably securing an insulator plug within a hole defined by asurrounding layer of insulating material disposed upon a preinsulatedmember comprising a resilient handle translatably secured to saidinsulator plug, and at least one extended portion affixed to saidresilient handle and extending radially outwardly and downwardly beyondthe periphery of said plug and into engagement within said insulatingmaterial layer when said plug is positioned in said hole.